1. Field of the Invention
The present invention relates to a printing apparatus, and a printing method and program.
2. Description of the Related Art
Related art will be described with reference to FIG. 12. FIG. 12 is a block diagram for illustrating a conventional example. A printing apparatus 72 includes a control unit 73, a rendering unit 74, and a print engine unit 75. The control unit 73 includes a transmission/reception unit 76, an input buffer 77, and an output spool 78. The transmission/reception unit 76 controls transmission/reception of data between the control unit 73 and the rendering unit 74. The input buffer 77 temporarily stores job data such as page description language (PDL) including images and documents from a host computer (Host PC) 71. The output spool 78 stores bitmap data converted by the rendering unit 74, and transmits the bitmap data to the print engine unit 75. The print engine unit 75 prints the bitmap data. The rendering unit 74 includes a transmission/reception unit 79 and a processing unit 710. The transmission/reception unit 79 controls transmission/reception of the data between the control unit 73 and the rendering unit 74. The processing unit 710 receives the job data stored in the input buffer 77 via the transmission/reception unit 79, and converts the job data into the bitmap data.
In the above-described conventional configuration, processing time used to convert the job data into the bitmap data is dependent on contents of the job data. Consequently, in order to surely transmit the bitmap data to the print engine unit 75 at a certain interval, the bitmap data after rendering processing is once spooled in the output spool 78 within the control unit 73. Then, at a stage when the bitmap data is gathered by a certain job unit, an operation of transmitting the bitmap data to the print engine unit 75 is performed.
In the printing apparatus with such configuration, there may be portions that are likely to cause format errors of the job data transmitted from external devices or errors of image data contained in the job data, and as a result the rendering processing may fail sometimes. In this case, of course, pages where errors have occurred will not be printed. In order to cope with such situations, there may be provided a step (pre-flight) for making checks for matching (checks of fonts or layouts) using an upstream software that operates on the host computer, before transmitting the data to the printer apparatus.
In Japanese Patent Application Laid-Open No. 2001-282497, error checks are made by the host computer before transmitting data to the printer apparatus, and the results are displayed on the host computer. Thereby error checks equivalent to the pre-flight have become possible.
However, in these configurations, the bitmap data for print of certain job units is spooled from the rendering unit 74, in the output spool 78 within the control unit 73, and accordingly a huge memory capacity is to be used. Since data transmission to the print engine unit 75 cannot be executed during the period until all the bitmap data is gathered, this would be a waste of time, during which the print engine unit 75 is stopped, becomes long and productivity is not increased. In other words, in the conventional technique, it is required to efficiently handle the rendering processing and the engine operation, and to enhance productivity of a printer.
In the case of photo book or the like, unless all pages are correctly printed, they have no commercial value. In such case, if any one of pages is in error, other pages which have been normally printed will be all eventually discarded, and thus commercial materials such as sheets and inks are wasted. In this connection, there is available a means such as a pre-flight in which prior inspection is performed in advance by the host computer as described above. However, there is a matter that error inspection of the job data is not necessarily performed before the data is populated, by depending on a function of an upstream application such as work flow software, or populating uninspected data into a printer by some users. Further, if an upstream step (work flow software) and a rendering processing module within the printer do not match, accurate check cannot be performed. In order to solve the above-described issue, there is a method for transmitting the data to the engine after the rendering of all pages has been completed, when printing of such as photo book is performed. However, in such a case a huge spool space is used, and further a job having a number of pages which exceeds a limited spool space cannot be printed.